A plurality of batteries are mounted on an electrical vehicle (hereinafter, referred to as an ‘EV’) or a hybrid electrical vehicle (hereinafter, referred to as an ‘HEV’), and accumulates electrical power for driving a vehicle running motor. Then, a temperature control device is additionally installed for these batteries with a view to removing heat generated from the batteries when charging the batteries and to maintaining a temperature range where electrical power is obtained with high efficiency.
As a state in which the batteries are charged and the heat generated therefrom is desired to be removed, there is a case of accumulating electrical power (so-called regenerated energy) obtained from a motor when the running vehicle is about to stop in addition to the case of replenishing electrical power to the batteries having a small amount of the accumulated electrical power due to the consumption by the running of the vehicle. On the contrary, in a case where the thermal condition around the vehicle is low such as in winter or the like, there is a case in which the batteries need to be warmed so as to obtain electrical power with high efficiency in a running mode. In this way, it is desirable that the temperature control device be designed to exhibit its original function not only in a vehicle stopping mode as in the case of replenishing electrical power to the batteries, but also in a vehicle running mode.
It should be noted that there is a tendency that the charging rate per unit of time when replenishing electrical power increases due to a demand for shortening the electrical power replenishing time in addition to an increase in accumulated electrical power amount for the purpose of extending a running distance. For this reason, the amount of heat generated from the batteries increases when charging the batteries, the battery becomes hot, and the charging efficiency degrades or the lifetime of the batteries is shortened. With such circumstances, there has been a demand for ensuring and improving the cooling performance of the temperature control device.
For this type of temperature control device of the battery, a water cooling type and an air cooling type are known, but from the viewpoint that the high heat exchange rate per unit of time with respect to the batteries can be obtained, the water cooling type cooling device has been gaining more attention (as the water cooling type, see Patent Document 1 below).
Furthermore, there has been proposed a refrigerant using system such as a heat pump cycle or a cooling cycle for an air-conditioner is addition to the water cooling type and the air cooling type. However, there is a need to facilitate the work of replacing the battery and the temperature control device in order to deal with the degradation or the failure of the battery, but the work of replacing the refrigerant is complex and the leakage of the collected refrigerant during the replacing work leads to the destruction of the environment. For these reasons, generally the refrigerant using system is not used.
Further, as the battery for the running of the vehicle, lithium, nickel hydrogen, and sodium-sulfur batteries have been developed. However, different from the conventional battery for the internal combustion engine, these batteries are used with the specification of, for example, a high voltage of 100 V or 350 V. Accordingly, it is essential to consider a method of preventing an electric shock accident in order to prevent a driver a passenger or a rescuer from being electrically shocked in the event of an accident in the EV or the HEV.
In the past, for the above-described electric shock preventing measures, there is known a method of detecting an impact generated in the event of a vehicle collision and breaking a battery circuit or changing wiring of the battery circuit so as to be maintained at a low voltage, or a method of detecting an impact generated in the event of a vehicle collision and injecting a chemical agent such as a cooling agent a neutralizing agent, an absorbing agent, or a fire extinguishing agent toward the battery so as to prevent the scattering of battery electrolyte produced by the damage of the battery itself (for the latter method, see Patent Document 2 below).